1. Technical Field
This invention relates to a method of and apparatus for generating behaviour in an object. Although the invention is not limited thereto, one application of particular interest is the generation of autonomous behaviour conveying body language in a virtual agent or object, for example an avatar.
2. Related Art
Animated objects, whether virtual (such as an avatar) or robotic (for example, a pet “toy”) are becoming increasingly sophisticated in their behaviour. In particular, there is a consumer demand for more realistic behaviour by virtual objects such as avatars and animated agents. In the context of this invention, an avatar is defined to be a visual representation of a user in a virtual environment, taking any appropriate form. An animated agent is an intelligent software based agent used for interactions with a user in a virtual environment, or for interactive entertainment. Similarly, the animated agent may take any appropriate form.
When an object is capable of having animated behaviour, it is desirable for a user who is relatively unskilled in programming to have the ability to personalise the object's behaviour. This is particularly so when the user is seeking, for example, to create a sense of individuality in a group setting, to enhance a role the object is playing, or to reflect the user's own personality. To make objects more interesting to their human users, it is desirable if a personality can be provided for an object, i.e., if the behaviour can be modified by the user to have certain traits that the user finds desirable.
To satisfy these demands, the behavioural models used to generate the behaviour in an animated object are becoming increasingly complex. This creates a conflict when a user relatively unskilled in programming wishes to modify the behaviour of an object, as they lack the expertise required to interface with the complex programs representing the behavioural model and modify the code underlying the behaviour.
Techniques to generate autonomous behaviour in an object and provide objects with personality which already known in the art are limited in their usefulness. Generally, a poor compromise is reached when providing an unskilled individual with suitable means to modify an object's behaviour and supporting complex behaviour by the object. This is especially so if a user wishes to modify the behaviour of an object in real-time.
Limited means to enable an unskilled user to modify the behaviour of a virtual object such as an avatar are disclosed in the art. For example, in U.S. Pat. No. 5,884,029 “User interaction with intelligent virtual objects, avatars, which interact with other avatars controlled by different users” by Brush II et al, a method and apparatus enabling a user to program a personality into an intelligent virtual object such as an avatar is disclosed. In this example, an avatar's personality is created by enabling the avatar to respond semi-autonomously to external stimulus using a pre-programmed set of responses. This method is of limited usefulness for many reasons, in particular as an unskilled user is not able to select which personality traits define the autonomous behaviour, and also as an unskilled user cannot modify the personality of an avatar in real-time.
In U.S. Pat. No. 6,212,502 “Modelling and Projecting Emotion and Personality from a Computer User Interface” by Ball et al, a method is disclosed which determines the probable emotional state of a user and then represents the user's emotional behaviour in a personal avatar to enhance the user's experience of a virtual world. This method is of limited usefulness as the user is not able to intervene and control the behaviour of the avatar if they wish the avatar's behaviour to differ from their own.
In U.S. Pat. No. 5,880,731 “Use of avatars with automatic gesturing and bounded interaction in on-line chat session” by Liles et al, a user can select from a limited menu certain gestures for an avatar to perform autonomously when the avatar is otherwise inactive. As the personality comprises selected gestures which are automatically displayed from time to time when the avatar is not performing deliberate actions under the control of the user, no modification to the behaviour is made to enhance the actions under the intentional control of the user.
The present invention seeks to provide apparatus for and a method of generating autonomous behaviour in an object which obviates and/or mitigates the disadvantages known in the art described hereinabove.